1. Field of the Invention
The present invention relates to a crystalline alumino-silicate catalyst having added silica contained within its interior structure, the manufacture of such catalyst and the use thereof.
2. Description of the Prior Art
U.S. Pat. No. 2,722,504 describes a catalyst of an activated oxide such as silica gel having a thin layer of an organosilicone polymer deposited thereon to increase the organophilic character of the contact surface and, as such, seeks to avoid silica deposition.
Crystalline aluminosilicate zeolites, modified by reaction with an organic substituted silane, have been described in U.S. Pat. No. 3,682,996 to Kerr and in U.S. Pat. No. 3,698,157 to Allen et al. The former of these patents describes, as novel compositions of matter, crystalline aluminosilicate esters made by reacting a crystalline aluminosilicate having an available hydrogen atom with an organic silane having a SiH group. The resulting compositions were disclosed as being catalysts useful for hydrocarbon processes, particularly hydrocracking. In the latter of the above patents, the use of ZSM-5 type crystalline aluminosilicate zeolites, modified by treatment with an organic-radical substituted silane are described, together with the use of such modified zeolites in chromotographic separation of the compounds contained in a C aromatic feed stock.
U.S. Pat. No. 4,145,315 discloses a method for the production of silica modified zeolite catalysts which are prepared by contacting the specific zeolite with an organic solvent solution such as hexane, of a silicone fluid, distillation of the hexane, and air calcination of the zeolite residue.